Configuring POS

This chapter describes advanced packet-over-SONET/SDH (POS) interface configuration for the ML-Series card. Basic POS interface configuration is included in Chapter 4 "Configuring Interfaces." For more information about the Cisco IOS commands used in this chapter, refer to the Cisco IOS Command Reference publication. POS operation on ONS Ethernet cards, including the ML-Series card, is described in Chapter 22 "POS on ONS Ethernet Cards."

POS on the ML-Series Card

Ethernet and IP data packets need to be framed and encapsulated into SONET/SDH frames for transport across the SONET/SDH network. This framing and encapsulation process is known as POS and is done in the ML-Series card. Chapter 22 "POS on ONS Ethernet Cards," explains POS in greater detail.

The ML-Series card takes the standard Ethernet ports on the front of the card and the virtual POS ports and includes them all as switch ports. Under Cisco IOS, the POS port is an interface similar to the other Ethernet interfaces on the ML-Series card. It is usually used as a trunk port. Many standard Cisco IOS features, such as IEEE 802.1 Q VLAN configuration, are configured on the POS interface in the same manner as on a standard Ethernet interface. Other features and configurations are done strictly on the POS interface. The configuration of features limited to POS ports is shown in this chapter.

ML-Series SONET and SDH Circuit Sizes

SONET is an American National Standards Institute (ANSI) standard (T1.1051988) for optical digital transmission at hierarchical rates from 51.840 Mbps (STS-1) to 2.488 Gbps (STS-48) and greater. SDH is the international standard for optical digital transmission at hierarchical rates from 155.520 Mbps (STM-1) to 2.488 Gbps (STM-16) and greater.

Both SONET and SDH are based on a structure that has a basic frame and speed. The frame format used by SONET is the synchronous transport signal (STS), with STS-1 being the base level signal at 51.84 Mbps. A STS-1 frame can be carried in an OC-1 signal. The frame format used by SDH is the synchronous transport module (STM), with STM-1 being the base level signal at 155.52 Mbps. A STM-1 frame can be carried in an OC-3 signal.

Both SONET and SDH have a hierarchy of signaling speeds. Multiple lower level signals can be multiplexed together to form higher level signals. For example, three STS-1 signals can be multiplexed together to form a STS-3 signal, and four STM-1 signals can be multiplexed together to form a STM-4 signal.

SONET circuit sizes are defined as STS-n, where n is a multiple of 51.84 Mbps and n is equal to or greater than 1. SDH circuit sizes are defined as STM-n, where n is a multiple of 155.52 Mbps and n is equal to or greater than 0. Table 5-1 shows STS and STM line rate equivalents.

VCAT

VCAT significantly improves the efficiency of data transport over SONET/SDH by grouping the synchronous payload envelopes (SPEs) of SONET/SDH frames in a nonconsecutive manner into VCAT groups. VCAT group circuit bandwidth is divided into smaller circuits called VCAT members. The individual members act as independent circuits.

Intermediate nodes treat the VCAT members as normal circuits that are independently routed and protected by the SONET/SDH network. At the terminating nodes, these member circuits are multiplexed into a contiguous stream of data. VCAT avoids the SONET/SDH bandwidth fragmentation problem and allows finer granularity for provisioning of bandwidth services.

The ONS 15454 SONET and ONS 15454 SDH ML-Series card VCAT circuits must also be routed over common fiber and be both bidirectional and symmetric. Only high order (HO) VCAT circuits are supported. The ML-Series card supports a maximum of two VCAT groups, with each group corresponding to one of the POS ports. Each VCAT group can contain two circuit members. A VCAT circuit originating from an ML-Series card must terminate on another ML-Series card or a CE-Series card. Table 5-2 shows supported VCAT circuit sizes for the ML-Series.

Caution Packet losses might occur when an optical fiber is reinserted or when a defect is cleared on members of the HW-LCAS split fiber routed circuits.

For step-by-step instructions on configuring an ML-Series card SONET VCAT circuit, refer to the "Create Circuits and VT Tunnels" chapter of the Cisco ONS 15454 Procedure Guide. For step-by-step instructions on configuring an ML-Series card SDH VCAT circuit, refer to the "Create Circuits and Tunnels" chapter of the Cisco ONS 15454 SDH Procedure Guide. For more general information on VCAT circuits, refer to the "Circuits and Tunnels" chapter of the Cisco ONS 15454 Reference Manualorthe Cisco ONS 15454 SDH Reference Manual.

Note ML-Series card POS interfaces normally send an alarm for signal label mismatch failure in the ONS 15454 STS path overhead (PDI-P) to the far end when the POS link goes down or when RPR wraps. ML-Series card POS interfaces do not send PDI-P to the far-end when PDI-P is detected, when a remote defection indication alarm (RDI-P) is being sent to the far end, or when the only defects detected are generic framing procedure (GFP)-loss of frame delineation (LFD), GFP client signal fail (CSF), virtual concatenation (VCAT)-loss of multiframe (LOM), or VCAT-loss of sequence (SQM).

Note For nodes not connected by DCC (open ended nodes), VCAT must be configured through TL-1.

SW-LCAS

A link capacity adjustment scheme (LCAS) increases VCAT flexibility by allowing the dynamic reconfiguration of VCAT groups without interrupting the operation of noninvolved members. Software link capacity adjustment scheme (SW-LCAS) is the software implementation of a LCAS-type feature. SW-LCAS differs from LCAS because it is not errorless and uses a different handshaking mechanism.

SW-LCAS on the ONS 15454 SONET/SDH ML-Series cards allows the automatic addition or removal of a VCAT group member in the event of a failure or recovery on a two-fiber bidirectional line switched ring (BLSR). The protection mechanism software operates based on ML-Series card link events. SW-LCAS allows service providers to configure VCAT member circuits on the ML-Series as protection channel access (PCA) circuits. This PCA traffic is dropped in the event of a protection switch, but is suitable for excess or noncommited traffic and can double the total available bandwidth on the circuit.

For step-by-step instructions on configuring SW-LCAS, refer to the "Create Circuits and VT Tunnels" chapter of the Cisco ONS 15454 Procedure Guideorthe "Create Circuits and Tunnels" chapter of the Cisco ONS 15454 SDH Procedure Guide. For more general information on SW-LCAS, refer to the "Circuits and Tunnels" chapter of the Cisco ONS 15454 Reference Manualorthe Cisco ONS 15454 SDH Reference Manual.

The following section lists guidelines to follow when the ML-MR-10 card includes a split fiber routing in a terminal and facility loopback on SW-LCAS circuits:

Note Make sure that you follow the guidelines and tasks listed in the following section. Not doing so will result in traffic going down on members passing through optical spans that do not have loopbacks.

•SW-LCAS circuit members must have J1 path trace set to manual.

•Transmit and receive traces must be unique.

•SW-LCAS circuits on ML-MR-10 must allow our of group (OOG) members on Trace Identifier Mismatch - Path (TIM-P).

•For members on split fiber routes, facility loopback must select the AIS option in CTC.

•Traffic hit is expected when loopback is applied. This is due to aysnchronous detection of VCAT defects and TIM-P detection on the other end of the circuit. This is acceptable since loopbacks are intrusive and affect traffic.

However, place members of an HW-LCAS circuit traversing an optical interface under maintenance in OOS,OOG (locked, outOfGroup) state before applying terminal/facility loopbacks.

Framing Mode, Encapsulation, and CRC Support

The ML-Series cards on the ONS 15454 and ONS 15454 SDH support two modes of the POS framing mechanism, GFP-F framing and HDLC framing (default). The framing mode, encapsulation, and CRC size on source and destination POS ports must match for a POS circuit to function properly. Chapter 22 "POS on ONS Ethernet Cards," explains the framing mechanisms, encapsulations, and cyclic redundancy check (CRC) bit sizes in detail.

Supported encapsulation and CRC sizes for the framing types are detailed in Table 5-3.

Note ML-Series card POS interfaces normally send PDI-P to the far-end when the POS link goes down or RPR wraps. ML-Series card POS interfaces do not send PDI-P to the far-end when PDI-P is detected, when RDI-P is being sent to the far-end or when the only defects detected are GFP LFD, GFP CSF, VCAT LOM or VCAT SQM.

Configuring POS Interface Framing Mode

You configure framing mode on an ML-Series card only through CTC. For more information on configuring framing mode in CTC, see Chapter 2 "CTC Operations."

Configuring POS Interface Encapsulation Type

The default Cisco EoS LEX is the primary encapsulation of ONS Ethernet cards. This encapsulation is used under HDLC framing with the protocol field set to the values specified in Internet Engineering Task Force (IETF) Request For Comments (RFC) 1841. Under GFP-F framing, the Cisco IOS CLI also uses the keyword lex. With GFP-F framing, the lex keyword is used to represent standard mapped Ethernet over GFP-F according to ITU-T G.7041.

To configure the encapsulation type for a ML-Series card, perform the following steps beginning in global configuration mode:

Manually shuts down the interface. Encapsulation changes on POS ports are allowed only when the interface is shut down (ADMIN_DOWN).

Step 3

Router(config-if)# encapsulation type

Sets the encapsulation type. Valid values are:

•hdlc—Cisco HDLC

•lex—(default) LAN extension, special encapsulation for use with Cisco ONS Ethernet line cards. When the lex keyword is used with GFP-F framing it is standard Mapped Ethernet over GFP-F according to ITU-T G.7041.

•ppp—Point-to-Point Protocol

Step 4

Router(config-if)# noshutdown

Restarts the shutdown interface.

Step 5

Router(config)# end

Returns to privileged EXEC mode.

Step 6

Router# copy running-config startup-config

(Optional) Saves configuration changes to NVRAM.

Configuring POS Interface CRC Size in HDLC Framing

To configure additional properties to match those of the interface at the far end, perform the following steps, beginning in global configuration mode:

Keep alive messages are on by default and are recommended, but not required.

The no form of this command turns off keep alive messages.

Step 3

Router(config-if)# end

Returns to the privileged EXEC mode.

Step 4

Router# copy running-config
startup-config

(Optional) Saves configuration changes to NVRAM.

SONET/SDH Alarms

The ML-Series cards report SONET/SDH alarms under both Cisco IOS and CTC/TL1. A number of path alarms are reported in the Cisco IOS console. Configuring Cisco IOS console alarm reporting has no effect on CTC alarm reporting. The "Configuring SONET/SDH Alarms" section specifies the alarms reported to the Cisco IOS console.

CTC/TL1 has sophisticated SONET/SDH alarm reporting capabilities. As a card in the ONS node, the ML-Series card reports alarms to CTC/TL-1 like any other ONS card. On the ONS 15454 SONET, the ML-Series card reports Telcordia GR-253 SONET alarms in the Alarms panel of CTC. For more information on alarms and alarm definitions, refer to the "Alarm Troubleshooting" chapter of the Cisco ONS 15454 Troubleshooting Guide or the Cisco ONS 15454 SDH Troubleshooting Guide.

Configuring SONET/SDH Alarms

All SONET/SDH alarms appear by default But to provision the reporting of SONET/SDH alarms on the Cisco IOS CLI, perform the following steps beginning in global configuration mode:

Permits console logging of selected SONET/SDH alarms. Use the no form of the command to disable reporting of a specific alarm.

The alarms are as follows:

•all—All alarms/signals

•encap—Path encapsulation mismatch

•pais—Path alarm indication signal

•plop—Path loss of pointer

•ppdi—Path payload defect indication

•pplm—Payload label, C2 mismatch

•prdi—Path remote defect indication

•ptim—Path trace identifier mismatch

•puneq—Path label equivalent to zero

•sd-ber-b3—PBIP BER in excess of SD threshold

•sf-ber-b3—PBIP BER in excess of SF threshold

Step 3

Router(config-if)# end

Returns to the privileged EXEC mode.

Step 4

Router# copy running-config
startup-config

(Optional) Saves configuration changes to NVRAM.

To determine which alarms are reported on the POS interface and to display the bit error rate (BER) thresholds, use the show controllerspos command, as described in the "Monitoring and Verifying POS" section.

Note Cisco IOS alarm reporting commands apply only to the Cisco IOS CLI. SONET/SDH alarms reported to the TCC2/TCC2P are not affected.

Configuring SONET/SDH Delay Triggers

You can set path alarms listed as triggers to bring down the line protocol of the POS interface. When you configure the path alarms as triggers, you can also specify a delay for the triggers using the pos trigger delay command. You can set the delay from 200 to 2000 ms. If you do not specify a time interval, the default delay is set to 200 ms.

To configure path alarms as triggers and specify a delay, perform the following steps beginning in global configuration mode:

Configures certain path defects as triggers to bring down the POS interface. The configurable triggers are as follows:

•all—All link down alarm failures

•ber_sd_b3—PBIP BER in excess of SD threshold failure

•ber_sf_b3—PBIP BER in excess of SD threshold failure (default)

•encap—Path Signal Label Encapsulation Mismatch failure (default)

•pais—Path Alarm Indication Signal failure (default)

•plop—Path Loss of Pointer failure (default)

•ppdi—Path Payload Defect Indication failure (default)

•pplm—Payload label mismatch path (default)

•prdi—Path Remote Defect Indication failure (default)

•ptim—Path Trace Indicator Mismatch failure (default)

•puneq—Path Label Equivalent to Zero failure (default)

Step 3

Router(config-if)# pos trigger
delaymillisecond

Sets waiting period before the line protocol of the interface goes down. Delay can be set from 200 to 2000 ms. If no time intervals are specified, the default delay is set to 200 ms.

Step 4

Router(config-if)# end

Returns to the privileged EXEC mode.

Step 5

Router# copy running-config
startup-config

(Optional) Saves configuration changes to NVRAM.

C2 Byte and Scrambling

One of the overhead bytes in the SONET/SDH frame is the C2 byte. The SONET/SDH standard defines the C2 byte as the path signal label. The purpose of this byte is to communicate the payload type being encapsulated by the SONET framing overhead (FOH). The C2 byte functions similarly to EtherType and Logical Link Control (LLC)/Subnetwork Access Protocol (SNAP) header fields on an Ethernet network; it allows a single interface to transport multiple payload types simultaneously. The C2 byte is not configurable. Table 5-5 provides C2 byte hex values.

Table 5-5 C2 Byte and Scrambling Default Values

Signal Label

SONET/SDH Payload Contents

0x01

LEX Encapsulation with 32-bit CRC with or without scrambling

0x05

LEX Encapsulation with 16-bit CRC with or without scrambling

0xCF

Cisco HDLC or PPP/BCP without scrambling

0x16

Cisco HDLC or PPP/BCP with scrambling

0x1B

GFP-F

Third-Party POS Interfaces C2 Byte and Scrambling Values

If a Cisco POS interface fails to come up when connected to a third-party device, confirm the scrambling and cyclic redundancy check (CRC) settings as well as the advertised value in the C2 byte. On routers from Juniper Networks, configuring RFC 2615 mode sets the following three parameters:

•Scrambling enabled

•C2 value of 0x16

•CRC-32

Previously, when scrambling was enabled, these third-party devices continued to use a C2 value of 0xCF, which did not properly reflect the scrambled payload.

Configuring SPE Scrambling

SPE scrambling is on by default. To configure POS SONET/SDH Payload (SPE) scrambling, perform the following steps, beginning in global configuration mode:

Disables payload scrambling on the interface. Payload scrambling is on by default.

Step 3

Router(config-if)# no shutdown

Enables the interface with the previous configuration.

Step 4

Router(config-if)# end

Returns to the privileged EXEC mode.

Step 5

Router# copy running-config
startup-config

(Optional) Saves configuration changes to NVRAM.

Monitoring and Verifying POS

The show controller pos [0 | 1] command (Example 5-1) outputs the receive and transmit values and the C2 value. Thus, changing the value on the local end does not change the value in the show controller command output.

Hardware is Packet/Ethernet over Sonet, address is 0011.2130.b340 (bia 0011.2130.b340)

MTU 1500 bytes, BW 145152 Kbit, DLY 100 usec,

reliability 255/255, txload 1/255, rxload 1/255

Encapsulation: Cisco-EoS-LEX, crc 32, loopback not set

Keepalive set (10 sec)

Scramble enabled

ARP type: ARPA, ARP Timeout 04:00:00

Last input 01:21:02, output never, output hang never

Last clearing of "show interface" counters 00:12:01

Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0

Queueing strategy: fifo

Output queue: 0/40 (size/max)

5 minute input rate 0 bits/sec, 0 packets/sec

5 minute output rate 0 bits/sec, 0 packets/sec

0 packets input, 0 bytes

Received 0 broadcasts (0 IP multicast)

0 runts, 0 giants, 0 throttles

0 parity

0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored

0 input packets with dribble condition detected

0 packets output, 0 bytes, 0 underruns

0 output errors, 0 applique, 0 interface resets

0 babbles, 0 late collision, 0 deferred

0 lost carrier, 0 no carrier

0 output buffer failures, 0 output buffers swapped out

0 carrier transitions

POS Configuration Examples

The following sections show ML-Series card POS configuration examples for connecting to other ONS Ethernet cards and POS-capable routers. These examples are only some of the ML-Series card configurations available to connect to other ONS Ethernet cards and POS-capable routers. For more specifics about the POS characteristics of ONS Ethernet cards, see Chapter 22 "POS on ONS Ethernet Cards."

Example 5-6 shows the commands associated with the configuration of the GSR-12000.

Example 5-6 GSR-12000 Configuration

hostname GSR

!

interface FastEthernet1/0

ip address 192.168.3.1 255.255.255.0

!

interface POS2/0

ip address 192.168.2.2 255.255.255.0

crc 32

encapsulation PPP

pos scramble-atm

!

router ospf 1

log-adjacency-changes

network 192.168.2.0 0.0.0.255 area 0

network 192.168.3.0 0.0.0.255 area 0

!

The default encapsulation for the ML-Series card is LEX and the corresponding default MTU is 1500 bytes. When connecting to an external POS device, it is important to ensure that both the ML-Series switch and the external device uses the same configuration for the parameters listed in Table 5-6.

Example 5-8 shows the commands associated with the configuration of ML-Series card A.

Example 5-8 ML-Series Card A Configuration

hostname ML_Series_A

!

interface FastEthernet0

ip address 192.168.1.1 255.255.255.0

!

interface POS0

ip address 192.168.2.1 255.255.255.0

crc 32

!

router ospf 1

log-adjacency-changes

network 192.168.1.0 0.0.0.255 area 0

network 192.168.2.0 0.0.0.255 area 0

CTC/TL1 has sophisticated SONET/SDH alarm reporting capabilities. As a card in the ONS node, the ML-Series card reports alarms to CTC/TL-1 like any other ONS card. On the ONS 15454 SONET, the ML-Series card reports Telcordia GR-253 SONET alarms in the Alarms panel of CTC. For more information on alarms and alarm definitions, refer to the "Alarm Troubleshooting" chapter of the Cisco ONS 15454 Troubleshooting Guide or the Cisco ONS 15454 SDH Troubleshooting Guide.

Configuring SONET/SDH Alarms

All SONET/SDH alarms are logged on the Cisco IOS CLI by default. But to provision or disable the reporting of SONET/SDH alarms on the Cisco IOS CLI, perform the following steps beginning in global configuration mode:

Permits logging of selected SONET/SDH alarms. Use the no form of the command to disable reporting of a specific alarm.

The alarms are as follows:

•all—All alarms/signals

•encap—Path encapsulation mismatch

•pais—Path alarm indication signal

•plop—Path loss of pointer

•ppdi—Path payload defect indication

•pplm—Payload label, C2 mismatch

•prdi—Path remote defect indication

•ptim—Path trace identifier mismatch

•puneq—Path label equivalent to zero

•sd-ber-b3—PBIP BER in excess of SD threshold

•sf-ber-b3—PBIP BER in excess of SF threshold

Step 3

Router(config-if)# end

Returns to the privileged EXEC mode.

Step 4

Router# copy running-config
startup-config

(Optional) Saves configuration changes to NVRAM.

To determine which alarms are reported on the POS interface and to display the bit error rate (BER) thresholds, use the show controllerspos command, as described in the "Monitoring and Verifying POS" section.

Note Cisco IOS alarm reporting commands apply only to the Cisco IOS CLI. SONET/SDH alarms reported to the TCC2/TCC2P are not affected.